Magnetic junk sub



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May 14, 1963 G. c. cRooKs MAGNETIC JUNK SUB Filed Dec. 5, 1960 @gil 2 sheets-sheet 1 www May 14, 1963 G. c. cRooKs 3,089,724

MAGNETIC JUNK SUB Filed Dec. 5, 1960 2 SheetswSheet 2 United States Patent O 3,089,724 MAGNETIC JUNI( SUB George C. Crooks, Calgary, Alberta, Canada, assigner to Sentinel Oil Tool Development da Services Ltd.,

Calgary, Alberta, Canada Filed Dee. 5, 1960, Ser. No. 73,812 12 Claims. (Cl. 294-655) My invention relates to new and useful improvements in magnetic junk subs.

In the drilling and casing `of oil wells, considerable magnetic junk occurs which can seriously damage the diamond drill bit normally used.

I have provided means for preventing the accumulation of said junk by the provision of a magnetic assembly situated preferably just above the drill head and in series with the drill stem which will attract and collect any magnetic junk occuring and retain same out of contact with the Walls of the drill bore thus maintaining the drill bore in a relatively clean condition and preventing damage cccuring through the drilling assemblies.

The principal object and essence of rny invention is therefore to provide a `device of the character herewithin described which is adapted to be situated above the drill head and to attract magnetic junk thereto for retention and eventual removal.

A further object of my invention is to provide a device of the character herewithin described which is easily assembled not `only to ya conventional drill stem string but Ialso is easily assembled without bolts or screws, to the principal mounting tube.

Another object of my invention is to provide a device of the character herewithin described which is frictionally mounted upon the central supporting tube so that if jamming does occur between the device and the walls of the drill bore, the tube `and `drill stem string can continue to rotate but the magnetic assembly becomes stationary thus preventing damage occuring thereto.

Another object of my invention -i-s to provide a device of the character herewithin described which incorporates a collecting basket below the magnetic assembly to catch junk which may be displaced partially during the withdrawal operation of the drill stem string.

Still another object of my invention is to provide a device of the character herewithin described which includes a plurality of sets of semi-circular magnetics so positioned and gapped that the magnetic ilux concentrates towards the junk collector portion in the center and is then di-rected in a circular fashion thus concentrating the magnetic effect at the magnetic gaps.

A further object of my invention is to provide a device of the character herewithin described which is relatively simple in construction, economical in manufacture, and otherwise well suited to the purpose tor which it is designed.

With the lforegoing objects in view, and such I'other ob- V jects and advantages as will become apparent to those skilled in the art to which Ithis invention relates as this speciiication proceeds, my invention consists essentially in the arrangement and construction of parts all as hereinafter more particularly described, reference being had to the accompanying drawings in which:

FIGURE l is a side elevation of my device sectioned along the longitudinal axis so that the upper portion of the View above the longitudinal axis is removed to show the interior thereof.

FIGURE 2 is Aa side elevation of the separator.

FIGURE 3 is an end view of FIGURE 2.

FIGURE 4 is a side elevation of one `of the end piece-s.

FIGURE 5 is a perspective view of one `of the spacers.

FIGURE 6 is an end view of the basket.

FIGURE 7 is a side elevation of FIGURE 6r.

ice

FIGURE 8 is 1a perspective view of one of the magnetic elements.

FIGURE 9 is an end view of one set of -the pole caps.

FIGURE l0 is a side elevation of FIGURE 9.

In the drawings like characters of reference indicate corresponding parts in the different iigures.

Proceeding therefore `to describe my invention in detail, reference should be made to the accompanying drawings in which I have illustrated a longitudinally extending main tube 10 having screw threaded tapered ends 1'1 and 12 and a shouldered portion 13 formed around the outer surface o-f the tube adjacent the end 12 thereof.

The tapered screw threaded end 12 is adapted to receive la standard coupler 14 which in turn is provided with internally screw threaded tapered end 1S to which can be attached one end Iof a conventional drill string (not illustrated).

A further coupler 16 is adapted to engage the screw threaded end 11 of the tube 10 and this coupler is provided with the externally tapered end 17 by which it may be secured to the adjacent length of drill rod (not illustrated).

From the foregoing it will ybe appreciated that the rod string rotative power is transmitted from Ione end to the other by the Iagency of the tube 10 which is centrally apertured so that the conventional lubricating and cleaning fluids can pass therethrough.

The coupler 16 is provided with an internal charntfer or taper 18 at the inner end thereof, the purpose of which will hereinafter become apparent.

A junk collecting basket 19 consisting of a cylindrical tube 20 is adapted to engage within a shoulder 21 on the inner end of the coupler 14 and is maintained in spaced and concentric arrangement with the tube 13 by means of a plurality cf internally extending ns or lugs 22 Welded to the inner surface of the -tube 20. These lugs bear against the outer surface of the tube 13 and the ends of the lugs butt up against one end 23 of the shouldered portion 13, being held lin place by the screw threaded engagement .of the coupler 14 with the end 12.

This forms a receptacle around the tube 10 which can retain any junk which may be displaced during the withdrawal of the device from the drill hole.

A cylindrical end piece 24 lits around the tube 10 and butts up against the other end 25 of the shouldered portion 13, said end piece having a recessed shoulder portion 26 formed upon the inner end thereof and recesses 27 formed on the inner end thereof, the purpose of which will hereinafter be described.

A further end piece 2S is provided at the opposite end of the assembly and is shown in detail in FIGURE 4. This end piece also is cylindrical and is provided with a shouldered portion 29 and recessed portion 30, the purn pose of which will hereinafter be described.

However, upon the outer side or end 31 of this end piece 28 is a concentrically located cylindrical portion 32, the periphery 33 of which is tapered to engage within the aforementioned taper 1'8 of the coupler 16.

When the entire device is assembled, a relatively small clearance 34, in the neighborhood of a few thousandths of an inch exists between one end of the tube 1G and the inner surface 35 of the coupler 16 and the tapered mating surfaces 33 and i8` act as a slip clutch for the assembly thus permitting same to remain stationary while the inner tube continues to rotate with the drill stem. This is because the only connection for rotation between the drill stem and the device is by the tapered frictional engagement of the walls 11. If the assembly is tightened Ito the extent necessary to provide sutlicient frictional engagement between these two portions, then of course the entire device will rotate with the drill stem. However if jamming occurs on the portion below the drillstem spaarzathen slippage will occur between these two portions thus preventing damage to the assembly. rThis prevents damage occurring to the assembly in the event that jamming takes place between the assembly and the walls of the drill hole.

A separator component 36 lis situated around the tube 10 between `the end pieces 24 and 2S and consists of a cylindrical portion 37 having a pair of arcuate fins 38 secured centrally thereon and extending radially therefrom as clearly shown in FIGURES 2 and 3. Furthermore the ends 39 of this separator are recessed as shown, the purpose of which will hereinafter become apparent.

FIGURES 9 and 10 of the drawings illustrate the pole pieces 40 which are arcuate in configuration and are internally formed as at 41. These pieces are welded to the tube 37 of the separator one upon each side of each of the fins 3S and these pole pieces are manufactured of a magnetic transmitting material such as mild steel.

Inasmuch as the separator 37 is manufactured from a non-magnetic material, it will be appreciated that the fins 38 will act as a separator for the magnetic elds of the magnetic assembly hereinafter to be described.

Arcuately formed pole plates 42 extend around the tube 10 and against the ends of the aforementioned pole pieces 40, the cross sectional configuration of the plates being similar to the cross sectional conguration of the pole pieces.

Beyond each of the pole plates are situated sets of magnetic elements 43 shown in detail in FIGURE 8. These are arcuate in shape and are adapted to register around the tube 10, there being two sets upon each side of the separator 37 diametrically opposite one another with relation to the tube 10.

Separating magnetic elements 43 from one another radially around the tube 10 is a plurality of arcuately formed spacers shown in FIGURE and indicated by the reference character 44 so that around the perimeter of the tube 1t) and upon each side of the separator' 37 is a magnet, a spacer, a magnet and a spacer. The ends 45 of the spacers 44 are adapted to engage with the aforementioned recessed end 39 of the separator in order to locate the magnets accurately with relation to the separator and pole pieces.

A tubular retainer 46 surrounds the magnets and the spacers, one end 47 of the tube engaging the shouldered portion 26 of the end piece 24 and 28, the other end 48 of the tube engaging recessed shoulders 49 formed on the pole pieces.

It should also be appreciated that the opposite ends 4S of the spacers engage within the recesses 30 of the end pieces.

With the items mounted around the tube as described, it will be apparent that tightening of the couplers 16 will clamp all of the components to the tube 19 in their desired relationship without the use of bolts, screws, etc. and that furthermore the components normally will rotate with the .tube 10 but can remain stationary if jamming occurs.

The location and spacing the pole pieces 40 around the separator 37 will give a pair of diametrically opposite magnetic gaps or recesses Si). If the ends 51 of the magnets upon one side of the tube 10 are north poles and the ends 52 of the magnets upon the other side of the tube 10 are south poles, magnetic flux is transmitted through the pole plates 42, to the pole pieces 40 and are separated one from the other by means of the tins 3S. The opposing magnetic uxes have thus only one direction in which they can flow and this is outwardly through the pole pieces at 90 degrees to the axis of the tube 10. Here it sweeps around the outside of the pole pieces and, to a lesser degree around the shaped portions 4l thereof to the opposite and attracting pole piece ends where it forms a powerful attraction across the gap between opposing ends.

There is thus formed a very strong concentrated magnetic field sweeping the walls of the well bore and attracting junk into the magnetic gap between the two magnetic assemblies.

Since various modifications can be made in my invention as hereinabove described, and many apparently widely diierent embodiments of same made within the spirit and scope of the claims without departing from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.

What I claim as my invention is:

1. A magnetic junk sub adapted to be secured in series with a drill stem string, comprising in combina tion, a non-magnetic longitudinally extending tube, a shouldered portion around said tube adjacent one end thereof, means on each end of said tube adapted to receive couplers of adjacent elements of said drill stem string, and a magnetic assembly frictionally mounted around said tube between said coupler and said shoulder, said magnetic assembly including a pair of spaced apart cylindrical end pieces surrounding said tube, one end of one of said cylindrical end pieces registering against said shouldered portion, one end of the other of said cylindrical end pieces being engaged by the adjacent end of one of said received adjacent drill string couplers, said magnetic assembly also including at least two sets of arcuately curved magnetic elements mounted around said tube and between said cylindrical end pieces, a pair of cylindrical sleeves surrounding said magnetic elements and engaging by one end of each thereof, said cylindrical end pieces, said magnetic assembly also including a centrally located magnetic separator around said tube and between said sets of magnetic elements, the other ends of said cylindrical tubes engaging said separator.

2. The device according to claim l in which said separator includes a cylindrical tube portion fitting around said first mentioned tube, a pair of radially extending tins centrally located on said tube portion and transversely thereto, and pairs of pole caps around said tube portion separated by said ns and adapted to form spaced gaps around said separator for the reception of junk magnetically attracted thereto.

t 3. The device according to claim 2 which includes pole plates between the said separator and said magnetic elements to concentrate the flux of said magnetic elements.

4. The device according to claim l in which one of said couplers has an internally tapered end portion, said end piece engaging said one coupler having an externally tapered end portion engageable by said coupler whereby said mating tapered surfaces rotate the components surrounding said tube, together with said tube, under normal circumstances but act as a slip clutch to said components if jamming occurs in the associated well bore.

5. The device `according to claim 2 in which one of said couplers has an internally tapered end portion, said end piece engaging said one coupler having an externally tapered end portion engageable by said coupler whereby said mating tapered surfaces rotate the components surrounding said tube, together with said tube, under normal circumstances but act as a slip clutch to said components if jamming occurs in the associated well bore.

6. The device according to claim 3 in which one of said couplers has an internally tapered end portion, said end piece engaging said one coupler having an externally tapered end portion engageable by said coupler where- A by said mating tapered surfaces rotate the components surrounding said tube, together with said tube, under normal circumstances but act as a slip clutch to said components if jamming occurs in the associated well bore.

7. The device according to claim 1 which includes a junk catching basket surrounding said tube but spaced from said magnetic assembly.

8. The device according to claim 2 which includes a junk catching basket surrounding said tube but spaced from said magnetic assembly.

9. The device according to claim 3 which includes a junk catching basket surrounding said tube but spaced junk catching basket `surrounding said tube but spaced 4from said magnetic assembly. fr 01H5 Sigg Hagletw assebly't 1 v A h, 1 1 d References Cited in the le of this patent e evice accor mg o c aim wici mc u es a junk catching basket ysurrounding said tube but spaced 5 UNITED STATES PATENTS from said magnetic assembly. 2,819,038 Eckel Ian- 7, 1958 12. The device according to claim 6 which includes a 10 567,222 Canada Dec. 9J 1958 

1. A MAGNETIC JUNK SUB ADAPTED TO BE SECURED IN SERIES WITH A DRILL STEM STRING, COMPRISING IN COMBINATION, A NON-MAGNETIC LONGITUDINALLY EXTENDING TUBE, A SHOULDERED PORTION AROUND SAID TUBE ADJACENT ONE END THEREOF, MEANS ON EACH END OF SAID TUBE ADAPTED TO RECEIVE COUPLERS OF ADJACENT ELEMENTS OF SAID DRILL STEM STRING, AND A MAGNETIC ASSEMBLY FRICTIONALLY MOUNTED AROUND SAID TUBE BETWEEN SAID COUPLER AND SAID SHOULDER, SAID MAGNETIC ASSEMBLY INCLUDING A PAIR OF SPACED APART CYLINDRICAL END PIECES SURROUNDING SAID TUBE, ONE END OF ONE OF SAID CYLINDRICAL END PIECES REGISTERING AGAINST SAID SHOULDERED PORTION, ONE END OF THE OTHER OF SAID CYLINDRICAL END PIECES BEING ENGAGED BY THE ADJACENT END OF ONE OF SAID RECEIVED ADJACENT DRILL STRING COUPLERS, SAID MAGNETIC ASSEMBLY ALSO INCLUDING AT LEAST TWO SETS OF ARCUATELY CURVED MAGNETIC ELEMENTS MOUNTED AROUND SAID TUBE AND BETWEEN SAID CYLINDRICAL END PIECES, A PAIR OF CYLINDRICAL SLEEVES SURROUNDING SAID MAGNETIC ELEMENTS AND ENGAGING BY ONE END OF EACH THEREOF, SAID CYLINDRICAL END PIECES, SAID MAGNETIC ASSEMBLY ALSO INCLUDING A CENTRALLY LOCATED MAGNETIC SEPARATOR AROUND SAID TUBE AND BETWEEN SAID SETS OF MAGNETIC ELEMENTS, THE OTHER ENDS OF SAID CYLINDRICAL TUBES ENGAGING SAID SEPARATOR. 